#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int main(void){
int a[10];
scanf("%d %d %d %d %d %d",&a[0],&a[1],&a[2],&a[3],&a[4],&a[5]);
int min=99999999,max=-1;
int minnum,maxnum;
for(int i=0;i<6;i++){
    if(min>=a[i]){min=a[i];minnum=i;}
    if(max<=a[i]){max=a[i];maxnum=i;}
}
printf("%.2lf\n",(double)(a[0]+a[1]+a[2]+a[3]+a[4]+a[5]-a[minnum]-a[maxnum])/4.0);



}